WO2017082130A1

WO2017082130A1 - Multilayer polyester film

Info

Publication number: WO2017082130A1
Application number: PCT/JP2016/082554
Authority: WO
Inventors: 理恵田川; 洋平山口
Original assignee: 東洋紡株式会社
Priority date: 2015-11-13
Filing date: 2016-11-02
Publication date: 2017-05-18
Also published as: JP2019090058A; TW201728461A; TWI599482B; JP2017095734A; CN108349228B; KR101893741B1; CN108349228A; JP6737364B2; JP6521264B2; KR20180042439A

Abstract

To provide a highly adhesive polyester film which has excellent balance among characteristics such as sliding properties and transparency, while exhibiting excellent handleability during the production thereof and in a post-process of a polarizing plate production process or the like for a liquid crystal display device, and which is not susceptible to scratches and has excellently low interference for suppression of iridescent irregularities, thereby being suitable for use in optical applications. A highly adhesive polyester film which has a coating layer on at least one surface, and wherein: the coating layer contains zirconia/titania mixture particles A, lubricating agent particles B and a binder resin; the content ratio of zirconia to the total mass of zirconia and titania in the zirconia/titania mixture particles A is 10-90% by mass; and the average particle diameter of the lubricating agent particles B is 200 nm or more.

Description

Laminated polyester film

The present invention relates to an easily-adhesive polyester film that can secure low interference and can solve the problem of rainbow unevenness and is excellent in transparency. More specifically, the present invention relates to an easily-adhesive polyester film that has few fine scratches and can be suitably used in high-definition optical applications.

A hard coat film in which a transparent hard coat layer is laminated is used on the front surface of displays such as touch panels, computers, televisions, and liquid crystal display devices, and decorative materials. Moreover, as a transparent plastic film of the base material, a transparent polyester film is generally used, and in order to improve the adhesion between the base material polyester film and the hard coat layer, these intermediate layers have easy adhesion. In many cases, a coating layer is provided.

The hard coat film is required to have temperature, humidity, light resistance, transparency, chemical resistance, scratch resistance, antifouling property, and the like. Moreover, since it is often used on the surface of a display or a decoration material, visibility and design are required. Therefore, in order to suppress glare and iris-like color caused by reflected light when viewed from an arbitrary angle, the antireflection of a multilayer structure in which a high refractive index layer and a low refractive index layer are laminated on top of the hard coat layer. It is common practice to provide a layer.

However, in recent years, there has been a demand for larger screens (larger areas) and higher definition in applications such as displays and decorative materials, and accordingly, there is a demand for suppression of iris-like colors (interference spots) especially under fluorescent lamps. The level is getting higher. In addition, fluorescent lamps are mainly in the three-wavelength form for daylight color reproducibility, and interference spots are more likely to appear. Further, there is an increasing demand for cost reduction by simplifying the antireflection layer. Therefore, what suppresses interference spots as much as possible is demanded only by a hard coat film without an antireflection layer.

The iris-like color (interference spots) of the hard coat film includes the refractive index (eg, 1.62-1.65) of the base polyester film and the refractive index (eg, 1.49) of the hard coat layer made of acrylic resin or the like. It is said that it occurs because of the large difference. In order to reduce the difference in the refractive index between the layers and prevent the occurrence of interference spots, a coating layer is provided on the polyester film of the base material, the refractive index difference between the polyester film and the coating layer, the refraction of the coating layer and the hard coat layer A method is disclosed in which the refractive index of the coating layer is controlled by the contents of the resin constituting the coating layer and the high refractive additive so as to reduce the difference in rate.

Conventionally, in the field of easily adhesive films for optics, there has been known a technique for reducing rainbow unevenness by including specific fine particles in an easily adhesive layer (see, for example, Patent Document 1). However, although this conventional technology seems to have achieved a certain result in terms of adhesion and rainbow unevenness suppression, there is a problem of easy scratching due to poor slipperiness, in order to increase slipperiness When other particles are added to the glass, there is a problem in that the balance between slipperiness and transparency, and low interference for reducing rainbow unevenness cannot be achieved.

JP 2007-203712 A

Due to the development of mobile technology, the use of mobile devices such as mobile phones, car navigation systems and e-books in the outdoor field is expanding. In addition, most of the portable devices are liquid crystal panel displays from the viewpoint of thinning. In such a field, for example, in a mobile phone equipped with a touch panel, as a hard coat film for protecting the surface of the display, a design on the back side of the hard coat film such as interference fringes and icon sheets due to reflected light on both interfaces contacting the coated surface In the application of the property, the defect of visibility due to interference fringes is becoming more apparent.

However, when a large amount of a high refractive additive is added so as to obtain a high low interference property, there are cases where transparency is impaired and low interference property and transparency cannot be achieved at the same time. In addition, since there are uses for high-definition displays, transparency may not be maintained even if a slip agent is added to improve the sliding property in order to suppress scratches.

Furthermore, in order to improve productivity in recent years, strong friction is applied to the coating layer as the post-processing speed increases, such as laminating hard coating layers and slitting, resulting in scratches on the coating layer that did not cause a problem in the past Variations in thickness and quality are becoming issues. In particular, since the resin used for increasing the refractive index is relatively high in hardness and brittle, the coating layer in which interference spots are suppressed tends to have a greater scratch resistance.

Therefore, an optically easy-adhesive polyester film having an effect of suppressing interference spots and having high adhesion to transparency and a hard coat layer without scratching the coating layer even during high-speed processing is being eagerly desired.

The present invention has been made against the background of the problems of the prior art. That is, the object of the present invention is excellent in the balance of characteristics such as slipperiness and transparency, excellent in handling properties in manufacturing and in subsequent processes such as a polarizing plate manufacturing process of a liquid crystal display device, less scratched, and rainbow unevenness. An object of the present invention is to provide an easy-adhesive polyester film that can be suitably used in optical applications that are also excellent in low interference for suppression.

As a result of intensive studies to achieve the above object, the present inventors have completed the present invention. That is, this invention consists of the following structures.
1. A polyester film having a coating layer on at least one side, wherein the coating layer contains zirconia / titania mixed particles A, lubricant particles B, and a binder resin, and is based on the total mass of zirconia and titania in the zirconia / titania mixed particles A. An easily adhesive polyester film having a zirconia content of 10 to 90% by mass and an average particle diameter of the lubricant particles B of 200 nm or more.
2. 2. The highly adhesive polyester film as described in the above item 1, wherein the zirconia / titania mixed particles A have an average particle size of 5 to 200 nm.
3. The easy-adhesive polyester film as described in 1 or 2 above, wherein the content of the lubricant particles B with respect to the solid content of the coating layer is 0.1 to 20% by mass.
4). 4. The highly adhesive polyester film as described in any one of 1 to 3 above, wherein the content of the zirconia / titania mixed particles A with respect to the solid content of the coating layer is 2 to 50% by mass.
5). Selected from the group consisting of a hard coat layer, an antiglare layer, an antiglare antireflection layer, an antireflection layer, and a low reflection layer on the coating layer of the easy-adhesive polyester film as described in any one of the above first to fourth A laminated polyester film having one or more functional layers.

According to the present invention, low interference that can suppress rainbow unevenness can be secured, the balance between transparency and slipperiness is excellent, scratches are small, and handling in the post-process such as the manufacturing process of a polarizing plate of a liquid crystal display device. It has become possible to provide an easy-adhesive polyester film that can be suitably used in optical applications with excellent properties.

(Polyester film)
The polyester film used as a substrate in the present invention is a film composed of a polyester resin, and a polyester film mainly comprising at least one of polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate is preferred. . Moreover, the film which a 3rd component monomer consists of copolyester in the above polyesters may be sufficient. Among these polyester films, a polyethylene terephthalate film is most preferable from the balance between physical properties and cost.

The polyester film may be a single layer or a multilayer. Moreover, as long as it exists in the range with the effect of this invention, each of these layers can contain various additives in a polyester resin as needed. Examples of the additive include an antioxidant, a light resistance agent, an antigelling agent, an organic wetting agent, an antistatic agent, an ultraviolet absorber, and a surfactant.

(Coating layer)
The easy-adhesive polyester film of the present invention is one in which an easy-adhesive coating layer is laminated on a polyester base film as described above. The coating layer contains zirconia / titania mixed particles A (hereinafter sometimes simply referred to as particles A), lubricant particles B (hereinafter sometimes simply referred to as particles B), and a binder resin.

Particle A is a zirconia / titania mixed particle. The mixed particles referred to in the present invention are a particle group containing both zirconia and titania in an aggregated state in which zirconia and titania are each dispersed in a single liquid and do not form a complex. Of course, in the coating layer, the liquid component is hardly evaporated in the drying process and the curing process. By including such particles A in the coating layer, the balance between slipperiness and transparency is excellent, and high transparency and low interference can be ensured. The liquid is preferably an aqueous liquid in order to easily form an application layer by a so-called in-line coating method described later.

The particles A may contain other components other than zirconia / titania, and may be inorganic particles or organic particles, and are not particularly limited. Examples of the inorganic particles are inert to metal oxides such as titanium, zirconium oxide, talc, and kaolinite, and polyesters such as calcium carbonate, calcium phosphate, and barium sulfate.

The ratio of the total mass of zirconia and titania to the mass of particles A (mixed particles are not included) is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass. % Or more. Of course, it may be 100% by mass. If the ratio of the total mass of zirconia and titania in the particles A is 70% by mass or more, it is preferable that a balance between slipperiness and transparency is achieved.

The ratio of the mass of zirconia to the total mass of zirconia and titania constituting the mixed particle A is preferably 10% by mass or more, more preferably 20% by mass or more, and further preferably 30% by mass or more. It is particularly preferably 40% by mass or more, more particularly preferably 50% by mass or more, and most preferably 55% by mass or more. When the ratio of the mass of zirconia to the total mass of zirconia and titania is 10% by mass or more, the surface roughness does not become excessively large, the slipping property with the guide roll becomes appropriate, and it is difficult to be damaged. Therefore, the haze does not increase and the transparency is excellent.

The ratio of the mass of zirconia to the total mass of zirconia and titania constituting the particles A is preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 80% by mass or less, particularly Preferably it is 77 mass% or less. If the ratio of the mass of zirconia to the total mass of zirconia and titania is 90% by mass or less, the surface roughness will not be too small, moderate slipperiness is maintained, handling properties are good, and unwinding Sometimes it is hard to get scratched and preferable.

The ratio of the mass of titania to the total mass of zirconia and titania constituting the particle A is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more, and particularly preferably 23% by mass. % Or more. When the ratio of the titania mass to the total mass of zirconia and titania is 10 mass% or more, the slipperiness is improved, the handling is improved, and the scratch resistance is improved. However, an increase in the ratio of the mass of titania to the total mass of zirconia and titania means a decrease in the ratio of the mass of zirconia, so that it is preferably 90% by mass or less, more preferably 80% by mass. Or less, more preferably 70% by mass or less, particularly preferably 60% by mass or less, still more preferably 50% by mass or less, and most preferably 45% by mass or less.

The average particle size of the particles A is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 15 nm or more, and particularly preferably 20 nm or more. It is preferable that the average particle diameter of the particles A is 5 nm or more because they are less likely to aggregate.

The average particle diameter of the particles A is preferably 200 nm or less, more preferably 150 nm or less, still more preferably 100 nm or less, and particularly preferably 60 nm or less. The average particle size of the particles A is preferably 200 nm or less because of good transparency.

Particle B consists of (1) silica, kaolinite, talc, light calcium carbonate, heavy calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, titanium dioxide, satin white, aluminum silicate Inorganic particles such as diatomaceous earth, calcium silicate, aluminum hydroxide, hydrous halloysite, magnesium carbonate, magnesium hydroxide, (2) acrylic or methacrylic, vinyl chloride, vinyl acetate, nylon, styrene / acrylic, Styrene / butadiene, polystyrene / acrylic, polystyrene / isoprene, polystyrene / isoprene, methyl methacrylate / butyl methacrylate, melamine, polycarbonate, urea, epoxy, urethane, phenol , Diallyl phthalate, but include organic particles of polyester or the like, to give an appropriate sliding property to the coating layer, silica is particularly preferably used.

The average particle size of the particles B is preferably 200 nm or more, more preferably 250 nm or more, still more preferably 300 nm or more, and particularly preferably 350 nm or more. It is preferable that the average particle diameter of the particles B is 200 nm or more because aggregation is difficult and slipperiness can be secured.

The average particle size of the particles B is preferably 2000 nm or less, more preferably 1500 nm, still more preferably 1000 nm, and particularly preferably 700 nm. It is preferable that the average particle size of the particles B is 2000 nm or less because transparency is maintained and the particles do not fall off.

The surface treatment of the particles A and B may be performed, and the surface treatment method includes physical surface treatment such as plasma discharge treatment and corona discharge treatment and chemical surface treatment using a coupling agent. Is preferred. As the coupling agent, an organoalkoxy metal compound (eg, titanium coupling agent, silane coupling agent) is preferably used. When the particles B are silica, silane coupling treatment is particularly effective. The surface treatment agent for particles B may be used in advance for surface treatment prior to preparation of the layer coating solution, or may be further added as an additive during preparation of the layer coating solution and contained in the layer. Of course, it may be used for the particles A.

The binder resin constituting the coating layer is not particularly limited as long as it provides easy adhesion, but specific examples of the polymer include polyester resin, acrylic resin, urethane resin, polyvinyl resin (polyvinyl alcohol, etc.), polyalkylene. Examples include glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, and starches. Among these, it is preferable to use a polyester resin, an acrylic resin, or a urethane resin from the viewpoint of particle retention and adhesion. Moreover, when considering familiarity with a polyester film, a polyester resin is optimal. These binder resins may be used in combination.

The polyester resin may be 100% by mass in the total solid component in the coating layer, but is preferably contained in an amount of 10% by mass to 90% by mass. More preferably, it is 20% by mass or more and 80% by mass or less. When the content of the polyester resin is 90% by mass or less, the adhesion with the hard coat layer under high temperature and high humidity is preferably maintained. On the contrary, when the content is 10% by mass or more, the adhesion with a polyester film under normal temperature and high temperature and high humidity is preferably maintained due to the presence of other urethane resins and the like.

In the present invention, in order to form a crosslinked structure in the coating layer, the coating layer may include a crosslinking agent. By containing a crosslinking agent, it becomes possible to further improve the adhesion under high temperature and high humidity. Specific examples of the crosslinking agent include urea, epoxy, melamine, isocyanate, oxazoline, and carbodiimide. Of these, melamine-based, isocyanate-based, oxazoline-based, and carbodiimide-based crosslinking agents are preferred because of the stability over time of the coating solution and the effect of improving adhesion under high-temperature and high-humidity treatment. Moreover, in order to promote a crosslinking reaction, a catalyst etc. can be used suitably as needed.

As content in the application layer of a crosslinking agent, 5 mass% or more and 50 mass% or less are preferable in all the solid components. More preferably, it is 10 mass% or more and 40 mass% or less. If it is 10% by mass or more, the strength of the resin of the coating layer is maintained, the adhesiveness under high temperature and high humidity is good, and if it is 40% by mass or less, the flexibility of the resin of the coating layer is maintained, Adhesion at normal temperature and high temperature and high humidity is maintained, which is preferable.

The content of the particles A in the coating layer is preferably 2% by mass or more, more preferably 3% by mass or more, still more preferably 4% by mass or more, and particularly preferably 5% by mass or more. When the content of the particles A in the coating layer is 2% by mass or more, the refractive index of the coating layer can be kept high, and low interference is effectively obtained, which is preferable.

The particle A content in the coating layer is preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, and particularly preferably 20% by mass or less. When the particle A content in the coating layer is 50% by mass or less, the film forming property is maintained, which is preferable.

The particle B content in the coating layer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably 1% by mass or more. When the content of the particles B in the coating layer is 0.1% by mass or more, an appropriate slip property is maintained, which is preferable.

The particle B content in the coating layer is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less. When the content of the particles B in the coating layer is 20% by mass or less, the haze is kept low, which is preferable in terms of transparency.

The film thickness of the coating layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, still more preferably 0.02 μm or more, and particularly preferably 0.05 μm or more. When the thickness of the coating layer is 0.001 μm or more, the adhesiveness is good, which is preferable.

The film thickness of the coating layer is preferably 2 μm or less, more preferably 1 μm or less, still more preferably 0.8 μm or less, and particularly preferably 0.5 μm or less. It is preferable that the coating layer has a thickness of 2 μm or less because there is no risk of blocking.

The coating layer may contain a surfactant for the purpose of improving leveling properties during coating and defoaming the coating solution. The surfactant may be any of cationic, anionic, and nonionic surfactants, but is preferably a silicone, acetylene glycol, or fluorine surfactant. These surfactants are preferably contained in the coating layer within a range that does not impair the effect of suppressing the iris-like color and the adhesion under a fluorescent lamp.

In order to impart other functionality to the coating layer, various additives may be included in a range that does not impair the effect of suppressing the iris-like color and the adhesiveness under a fluorescent lamp. Examples of the additive include fluorescent dyes, fluorescent brighteners, plasticizers, ultraviolet absorbers, pigment dispersants, foam suppressors, antifoaming agents, and preservatives.

As the coating method, any of a so-called in-line coating method in which a polyester base film is simultaneously formed and a so-called off-line coating method in which a polyester base film is formed and then coated with a coater can be applied. An in-line coating method is more efficient and more preferable.

As a coating method, any known method can be used as a method for applying a coating solution to a polyethylene terephthalate (hereinafter abbreviated as PET) film. For example, reverse roll coating method, gravure coating method, kiss coating method, die coater method, roll brush method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, impregnation coating method, curtain coating method, etc. It is done. These methods are applied alone or in combination.

In the present invention, as a method of providing a coating layer on a polyester film, a method of coating and drying a coating solution containing a solvent, particles and a resin on the polyester film can be mentioned. Examples of the solvent include organic solvents such as toluene, water, and a mixed system of water and a water-soluble organic solvent. Preferably, water alone or a mixture of a water-soluble organic solvent and water is used from the viewpoint of environmental problems. preferable.

The solid content concentration of the coating liquid is preferably 2% by mass or more, and more preferably 4% by mass, although it depends on the type of binder resin and the type of solvent. The solid content concentration of the coating liquid is preferably 35% by mass or less, and more preferably 15% by mass or less.

The drying temperature after coating also depends on the type of binder resin, the type of solvent, the presence or absence of a crosslinking agent, the solid content concentration, etc., but is preferably 80 ° C. or higher, and preferably 250 ° C. or lower.

The surface roughness (Ra) of the coating layer is related to the slipperiness of the surface of the coating layer, and is preferably 0.01 nm or more, more preferably 0.1 nm or more, and further preferably 0.2 nm or more. And particularly preferably 0.5 nm or more. On the other hand, the upper limit of the surface roughness (Ra) of the coating layer is preferably 200 nm or less, more preferably 100 nm or less, still more preferably 80 nm or less, and particularly preferably 50 nm or less.

(Manufacture of easily adhesive polyester film for optics)
The easily adhesive polyester film for optics of the present invention can be manufactured according to a general method for manufacturing a polyester film. For example, the polyester resin is melted and the non-oriented polyester extruded and formed into a sheet shape is stretched in the longitudinal direction by utilizing the speed difference of the roll at a temperature equal to or higher than the glass transition temperature, and then stretched in the transverse direction by a tenter. The method of performing heat processing is mentioned.

The polyester film of the present invention may be a uniaxially stretched film or a biaxially stretched film, but when the biaxially stretched film is used as a protective film on the front surface of the liquid crystal panel, it is observed from directly above the film surface. However, rainbow-like color spots are not seen, but care must be taken because rainbow-like color spots may be observed when observed from an oblique direction.

This phenomenon is that a biaxially stretched film is composed of refractive index ellipsoids having different refractive indexes in the running direction, width direction, and thickness direction, and the retardation becomes zero depending on the light transmission direction inside the film (refractive index ellipse). This is because there is a direction in which the body appears to be a perfect circle. Therefore, when the liquid crystal display screen is observed from a specific oblique direction, a point where the retardation becomes zero may be generated, and a rainbow-like color spot is generated concentrically around that point. When the angle from the position directly above the film surface (normal direction) to the position where the rainbow-like color spots are visible is θ, the angle θ increases as the birefringence in the film increases, and the rainbow-like color increases. Spots are difficult to see. The biaxially stretched film tends to reduce the angle θ, and therefore the uniaxially stretched film is more preferable because rainbow-like color spots are less visible.

However, a perfect uniaxial (uniaxial symmetry) film is not preferable because the mechanical strength in the direction orthogonal to the orientation direction is significantly reduced. The present invention has biaxiality (biaxiality) in a range that does not substantially cause rainbow-like color spots or a range that does not cause rainbow-like color spots in the viewing angle range required for a liquid crystal display screen. It is preferable.

(Laminated polyester film)
The laminated polyester film used mainly for optical applications of the present invention is a hard coat layer comprising an electron beam, an ultraviolet curable acrylic resin, a siloxane thermosetting resin, or the like on the coating layer of the easily adhesive polyester film of the present invention. Etc. are provided.

It is also a preferable form to provide a functional layer on the coating layer of the easily adhesive polyester film of the present invention. Functional layers are anti-glare layers, anti-glare anti-reflection layers, anti-reflection layers, low reflection layers, and the like in addition to the hard coat layers described above for the purpose of preventing reflections, suppressing glare, suppressing rainbow unevenness, and suppressing scratches. A layer having functionality such as an antistatic layer. As the functional layer, various types known in the art can be used, and the type is not particularly limited. Hereinafter, each functional layer will be described.

For example, in the formation of the hard coat layer, a known hard coat layer can be used, and is not particularly limited, but is polymerized by drying, heat, chemical reaction, or irradiation with any of electron beam, radiation, and ultraviolet rays. And / or a reactive resin compound can be used. Examples of such curable resins include melamine-based, acrylic-based, silicone-based, and polyvinyl alcohol-based curable resins. However, in terms of obtaining high surface hardness or optical design, a photocurable acrylic curable resin is used. Resins are preferred. As such an acrylic curable resin, a polyfunctional (meth) acrylate monomer or an acrylate oligomer can be used. Examples of the acrylate oligomer include polyester acrylate, epoxy acrylate, urethane acrylate, Examples include ether acrylate, polybutadiene acrylate, and silicone acrylate. A coating composition for forming the optical functional layer can be obtained by mixing a reactive diluent, a photopolymerization initiator, a sensitizer and the like with these acrylic curable resins.

The hard coat layer may have an antiglare function (antiglare function) that scatters external light. The antiglare function (antiglare function) can be obtained by forming irregularities on the surface of the hard coat layer. At this time, the haze of the film is ideally preferably 0 to 50%, more preferably 0 to 40%, and particularly preferably 0 to 30%. Of course, 0% is ideal and may be 0.2% or more, or 0.5% or more.

Therefore, the film of the present invention is mainly used for optical films in general, such as prism lens sheets, AR (anti-reflection) films, hard coat films, diffusion plates, anti-crush films, LCDs, flat TVs, CRTs, etc. It can be suitably used for a base film for a member, a near-infrared absorbing filter as a member on a front plate for a plasma display, a transparent conductive film such as a touch panel or electroluminescence, and the like.

More specifically, the acrylic resin curable by electron beam or ultraviolet rays for forming the hard coat layer described above has an acrylate functional group, for example, a relatively low molecular weight polyester resin, polyether resin, acrylic resin. , Epoxy or urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, oligomers or prepolymers of polyfunctional compounds such as polyhydric alcohols or prepolymers and ethyl (meth) as a reactive diluent Monofunctional monomers such as acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone, and polyfunctional monomers such as trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate Relate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol Those containing di (meth) acrylate or the like can be used.

However, in the case of an electron beam or ultraviolet curable resin, as a photopolymerization initiator in the above-mentioned resin, acetophenones, benzophenones, Michler benzoylbenzoate, α-amyloxime ester, tetramethyltyramium monosulfide, thioxanthone In addition, n-butylamine, triethylamine, tri-n-butylphosphine or the like can be used as a photosensitizer.

In addition, the silicone-based (siloxane-based) thermosetting resin can be produced by hydrolyzing and condensing a single or a mixture of two or more organosilane compounds under an acid or base catalyst. In particular, in the case of low reflection, it is better to improve the low refractive index and stain resistance by mixing and hydrolyzing and condensing one or more fluorosilane compounds.

(Manufacture of laminated polyester film)
Although the manufacturing method of the laminated polyester film in this invention is demonstrated taking an easily-adhesive polyester film as an example, naturally it is not limited to this.

The above-mentioned electron beam, UV curable acrylic resin or siloxane thermosetting resin is applied to the surface of the easy-adhesive polyester film. When the coating layer is provided on both surfaces, it is coated on at least one coating layer surface. Although it is not necessary to dilute the coating solution in particular, there is no particular problem even if it is diluted with an organic solvent as required, such as the viscosity, wettability, coating thickness, etc. The coating layer is obtained by curing the coating layer by applying an electron beam or ultraviolet ray and heating according to the curing conditions of the coating solution after applying the coating solution to the above-mentioned film and drying it as necessary. Then, a hard coat layer is formed.

In the present invention, the thickness of the hard coat layer is preferably 1 to 15 μm. It is preferable that the thickness of the hard coat layer is 1 μm or more, since the effects on the chemical resistance, scratch resistance, antifouling property, etc. as the hard coat layer are efficiently exhibited. On the other hand, when the thickness is 15 μm or less, the flexibility of the hard coat layer is maintained, and there is no possibility that cracks or the like occur, which is preferable.

As scratch resistance, it is preferable that scratches are not noticeable visually when the coated surface is worn with a black mount. If scratches are not conspicuous in the above evaluation, it is difficult to be damaged when passing through the guide roll, which is preferable from the viewpoint of handling properties.

The lower limit of the static friction coefficient (μs) is preferably 0.3, and if it is 0.3 or more, there is no problem of slipping too much, so it is easy to wind up with a hard chrome plating roll or the like in the manufacturing process. Handling properties and blocking resistance are preferably maintained. The upper limit of the static friction coefficient (μs) is preferably 0.5, and it is preferably 0.5 or less because there is no fear of scratching the film that becomes the contact surface during winding.

The lower limit of the dynamic friction coefficient (μd) is preferably 0.4, and if it is 0.4 or more, there is no problem of slipping too much, so that it is easy to wind up with a hard chrome plating roll or the like in the manufacturing process. Handling properties and blocking resistance are preferably maintained. The upper limit of the dynamic friction coefficient (μd) is preferably 0.6, and it is preferably 0.6 or less because there is no fear of scratching the film that becomes the contact surface during winding.

Since the polyester film of the present invention is mainly used as an easily adhesive film for optics, it is preferable that the polyester film has high transparency. The lower limit of the haze is ideally 0%, and the closer to 0%, the more preferable. The upper limit of haze is preferably 2%, and it is preferably 2% or less because the light transmittance is good and a clear image can be obtained in a liquid crystal display device. The haze of the polyester film can be measured, for example, according to a method described later.

The lower limit of the adhesiveness between the easy-adhesive layer coating layer and the hard coat layer is preferably 80%, and the upper limit is preferably 100%, as evaluated by the measurement method described later. It can be said that the adhesiveness of a coating layer and a hard-coat layer is fully hold | maintained as it is 80% or more.

The lower limit is preferably 10%, and the upper limit of the high temperature and high humidity adhesion is preferably 100%. is there. When it is 10% or more, the adhesiveness between the easy-adhesion layer and the hard coat layer is fully satisfied under high temperature and high humidity conditions, and the passability in the post-processing step is fully satisfied. More preferably, it is 50% or more.

The polyester film for protecting a polarizer formed with a hard coat is preferably not able to confirm interference spots by the evaluation method described later, and if the interference spots by the evaluation method cannot be confirmed, the visibility of the liquid crystal image device becomes good. preferable.

The easy-adhesive polyester film of the present invention can be used for various applications, but is preferably used in the production process of a polarizing plate used in a liquid crystal display device, and particularly preferably used as a protective film for a polarizer constituting the polarizing plate. It is what Usually, the polarizer is often made of polyvinyl alcohol, and the easy-adhesive polyester film of the present invention is bonded to the polarizer using an adhesive made of polyvinyl alcohol or a crosslinking agent or the like, if necessary. In that case, it is more preferable to use the coating layer of the easily adhesive polyester film of the present invention not on the surface to be bonded to the polarizer but on the opposite surface. The surface of the easy-adhesive polyester film of the present invention to be bonded to the polarizer contains an easy-adhesion containing, for example, a polyester resin, a polyvinyl alcohol resin, and a crosslinking agent as described in International Publication No. 2012/105607. It is preferable that the layers are laminated.

Next, the present invention will be described in detail with reference to Examples, Comparative Examples, and Reference Examples, but the present invention is naturally not limited to the following Examples. The evaluation method used in the present invention is as follows.

(1) Average particle size [measurement method using a scanning electron microscope]
The average particle diameter of the above particles can be measured by the following method. Take a picture of the particles with a scanning electron microscope (SEM) and at a magnification such that the size of one smallest particle is 2-5 mm, the maximum diameter of 300-500 particles (between the two most distant points) Distance) is measured, and the average value is taken as the average particle diameter. The average particle diameter of the particles present in the coating layer in the present invention can be measured by the measurement method.

(Dynamic light scattering method)
The average particle diameter of the particles can also be determined by a dynamic scattering method at the time of producing the particles and film. The sol was diluted with a dispersion medium, measured with a submicron particle analyzer N4 PLUS (manufactured by Beckman Coulter, Inc.) using parameters of the dispersion medium, and calculated by a cumulant method to obtain an average particle diameter. In the dynamic light scattering method, the average particle diameter of the particles in the sol is observed. When there is aggregation between the particles, the average particle diameter of the aggregated particles is observed.

(2) Refractive index of particles
The refractive index of the particles can be measured by the following method. After the inorganic particles are dried at 150 ° C., the powder pulverized in a mortar is immersed in the solvent 1 (having a lower refractive index than the particles), and then the solvent 2 (having a higher refractive index than the particles) is little by little transparent. Added until. The refractive index of this solution was measured using an Abbe refractometer (Abago Abbe refractometer). The measurement was performed at 23 ° C. and D line (wavelength 589 nm). The solvent 1 and the solvent 2 are selected so that they can be mixed with each other. Depending on the refractive index, for example, 1,1,1,3,3,3-hexafluoro-2-propanol, 2-propanol, chloroform, tetrachloride Examples of the solvent include carbon, toluene, and glycerin.

(3) Haze of easy-adhesive polyester film The haze of the easy-adhesive polyester film was measured using a turbidimeter (Nippon Denshoku, NDH2000) based on JIS K 7136: 2000.

(4) Adhesiveness On the easy-adhesion layer of the polyester film obtained in the example, the hard coat layer described in the item of formation of the hard coat layer was formed. The adhesion film between the hard coat layer and the substrate film is determined for the easy-adhesion polyester film having a hard coat formed in accordance with the description in 8.5.1 of JIS-K5400-1990.

Specifically, 100 grid-like cuts that penetrate the hard coat layer and reach the base film are made on the hard coat layer surface using a cutter guide having a gap interval of 2 mm. Next, a cellophane adhesive tape (manufactured by Nichiban Co., Ltd., No. 405; 24 mm width) is attached to the grid-shaped cut surface and rubbed with an eraser to be completely attached. Then, the cellophane adhesive tape is peeled off from the hard coat layer surface of the hard coat laminated polarizer protective film vertically, and the number of squares peeled off from the hard coat layer surface of the hard coat laminate polarizer protective film is visually counted, and the following formula From the above, the adhesion between the hard coat layer and the substrate film is determined. In addition, what has peeled partially among squares is counted as a square which peeled.

Adhesiveness (%) = {1− (number of peeled squares / 100)} × 100

(5) Moisture and heat resistance The above-mentioned laminated film for protecting a polarizer formed with a hard coat is left in an environment of 85 ° C. and 85 RH% for 500 hours in a high-temperature and high-humidity tank, and then the hard-coated laminated polarizer protective film is taken out. And left at room temperature for 12 hours. Thereafter, the adhesion between the hard coat layer and the substrate film was determined in the same manner as described above, and the heat and moisture resistance was obtained.

(6) Static friction coefficient, dynamic friction coefficient (μs, μd)
The friction coefficient of the polyester film obtained in the example was measured using Tensilon (Toyo Baldwin, RTM-100) in accordance with JIS K7125-1999 Plastic Film and Sheet Friction Coefficient Test Method.

(7) Interference fringe improvement (iris color)
A hard coat layer was formed on the easy-adhesion layer of the optically-adhesive polyester film obtained in each Example. The optically easy-adhesive polyester film on which a hard coat was formed was cut into an area of 10 cm (film width direction) × 15 cm (film longitudinal direction) to prepare a sample film. A black glossy tape (manufactured by Nitto Denko Corporation, vinyl tape No. 21; black) was bonded to the surface opposite to the hard coat layer surface of the obtained sample film. With the hard coat surface of this sample film as the top surface, using a three-wavelength daylight white color (National Parlook, FL 15EX-N 15W) as the light source, the positional relationship (distance 40 to (60 cm, angle of 15 to 45 °).

The results of visual observation are ranked according to the following criteria. The observation is performed by five people who are familiar with the evaluation, and the highest rank is the evaluation rank. If two ranks have the same number, the center of the rank divided into three is adopted. For example, ◎ and ○ are 2 people each and △ is 1 person, ○ is ◎, ◎ is 1 person and ○ and △ are 2 people each, ○, ◎ and △ are 2 people each and ○ is 1 In the case of names, ○ is adopted.
◎: Iridescent colors are not observed even when observed from all angles. ○: Some iris colors are observed at some angles. △: Slightly iris colors are observed. X: Clear iris colors are observed. Be done

(8) Scratch resistance of coating layer Attaching 3 cm (film width direction) x 20 cm (film longitudinal direction) of an optically-adhesive polyester film to a friction fastness tester (RT-200, manufactured by Daiei Kagaku Seisakusho) Using a black mount (thickness 80 μm, arithmetic average surface roughness 0.03 μm) at the contact portion between the load head (2 cm × 2 cm, 200 g) with a weight (300 g) and the sample film, 10c
The distance m was reciprocated 3 times at a speed of 20 seconds per reciprocation. The sample film obtained on the black mount was placed and visually checked for scratches.
○: Scratches can not be confirmed on the black mount, or slight scratches can be confirmed depending on the location △: Slight scratches can be confirmed overall on the black mount ×: Scratches clearly confirmed on the black mount it can

(9) Glass transition temperature
Based on JIS K7121-1987, using a differential scanning calorimeter (Seiko Instruments, DSC6200), 10 mg of a resin sample was heated at a rate of 20 ° C / min over a temperature range of 25 to 300 ° C and obtained from a DSC curve. The extrapolated glass transition start temperature was defined as the glass transition temperature.

(10) Number average molecular weight
0.03 g of resin was dissolved in 10 ml of tetrahydrofuran, and GPC-LALLS apparatus low angle light scattering photometer LS-8000 (manufactured by Tosoh Corporation, tetrahydrofuran solvent, reference: polystyrene) was used. Column temperature was 30 ° C., flow rate was 1 ml / min, column (Shodex KF-802, 804, 806 manufactured by Showa Denko KK) was used to measure the number average molecular weight.

(11) Resin composition
The resin was dissolved in deuterated chloroform, 1H-NMR analysis was performed using a nuclear magnetic resonance analyzer (NMR) Gemini-200 manufactured by Varian, and the mol% ratio of each composition was determined from the integral ratio.

(12) Surface roughness (Ra)
Based on JIS-B0601-2001, Ra was measured with Surfcom (registered trademark) 304B (manufactured by Tokyo Seimitsu Co., Ltd.). The measurement conditions were a cutoff of 0.08 μm, a stylus radius of 2 μm, a measurement length of 0.8 mm, and a measurement speed of 0.03 mm / second.

(Polyester resin polymerization)
In a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser, 194.2 parts by weight of dimethyl terephthalate, 184.5 parts by weight of dimethyl isophthalate, 14.8 parts by weight of dimethyl-5-sodium sulfoisophthalate, The mixture was charged with 233.5 parts by mass of diethylene glycol, 136.6 parts by mass of ethylene glycol, and 0.2 parts by mass of tetra-n-butyl titanate, and subjected to a transesterification reaction at a temperature of 160 to 220 ° C. over 4 hours. Next, the temperature was raised to 255 ° C., the pressure of the reaction system was gradually reduced, and the mixture was reacted for 1 hour 30 minutes under a reduced pressure of 30 Pa to obtain a copolymerized polyester resin (I). The obtained copolyester resin (I) was light yellow and transparent. The reduced viscosity of the copolyester resin (I) was measured and found to be 0.70 dl / g. The glass transition temperature by DSC was 40 ° C., and the number average molecular weight was 20000.
The composition of the copolyester resin (I) is as follows.
・ Dicarboxylic acid formation: terephthalic acid 49 mol%, isophthalic acid 48 mol%, 5-sodium isophthalic acid 3 mol%
-Diol component: ethylene glycol 40 mol%, diethylene glycol 60 mol%

(Manufacture of polyester aqueous dispersion)
In a reactor equipped with a stirrer, a thermometer and a reflux device, 30 parts by mass of the copolymerized polyester resin (I) and 15 parts by mass of ethylene glycol-n-butyl ether were added and heated at 110 ° C. to stir and dissolve the resin. After the resin was completely dissolved, 55 parts by mass of water was gradually added to the polyester solution while stirring. After the addition, the liquid was cooled to room temperature while stirring to prepare a milky white polyester aqueous dispersion (Iα) having a solid content of 28.2% by mass.

(Manufacture of polyurethane water dispersion)
In a four-necked flask equipped with a stirrer, a Dimroth condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 43.75 parts by mass of 4,4-dicyclohexylmethane diisocyanate, 12.85 parts by mass of dimethylolbutanoic acid, 153.41 parts by mass of polyhexamethylene carbonate diol having a number average molecular weight of 2000, 0.03 parts by mass of dibutyltin dilaurate, and 84.00 parts by mass of acetone as a solvent were added and stirred at 75 ° C. for 3 hours in a nitrogen atmosphere. It was confirmed that the liquid reached a predetermined amine equivalent. Next, after the temperature of this reaction liquid was lowered to 40 ° C., 8.77 parts by mass of triethylamine was added to obtain a polyurethane prepolymer solution. Next, 450 g of water was added to a reaction vessel equipped with a homodisper capable of high-speed stirring and adjusted to 25 ° C., while stirring and mixing at 2000 min ⁻¹ , the polyurethane prepolymer solution was added and dispersed in water. . Thereafter, a part of acetone and water was removed under reduced pressure to prepare a water-soluble polyurethane resin solution (II) having a solid content of 37% by mass. The obtained polyurethane resin (II) had a glass transition temperature of −30 ° C.

(Polymerization of block polyisocyanate crosslinking agent)
100 parts by mass of a polyisocyanate compound having an isocyanurate structure using hexamethylene diisocyanate as a raw material (manufactured by Asahi Kasei Chemicals, Duranate TPA) in a flask equipped with a stirrer, a thermometer and a reflux condenser, 55 parts by mass of propylene glycol monomethyl ether acetate, 30 parts by mass of polyethylene glycol monomethyl ether (average molecular weight 750) was charged and held at 70 ° C. for 4 hours in a nitrogen atmosphere. Thereafter, the reaction solution temperature was lowered to 50 ° C., and 47 parts by mass of methyl ethyl ketoxime was added dropwise. The infrared spectrum of the reaction solution was measured to confirm that the absorption of the isocyanate group had disappeared, and a block polyisocyanate aqueous dispersion (III) having a solid content of 75% by mass was obtained.

(Polymerization of oxazoline crosslinking agent)
A mixture of 58 parts by mass of ion-exchanged water and 58 parts by mass of isopropanol as an aqueous medium in a flask equipped with a thermometer, a nitrogen gas introduction tube, a reflux condenser, a dropping funnel, and a stirrer, and a polymerization initiator (2, 2 4 parts by mass of '-azobis (2-amidinopropane) dihydrochloride) was added. Meanwhile, in a dropping funnel, 16 parts by mass of 2-isopropenyl-2-oxazoline as a polymerizable unsaturated monomer having an oxazoline group, methoxypolyethylene glycol acrylate (average number of moles of ethylene glycol added: 9 moles, Shin Nakamura Chemical) A mixture of 32 parts by mass and 32 parts by mass of methyl methacrylate was added, and the mixture was added dropwise at 70 ° C. for 1 hour in a nitrogen atmosphere. After completion of the dropwise addition, the reaction solution was stirred for 9 hours and cooled to obtain a water-soluble resin (IV) having an oxazoline group having a solid concentration of 40% by mass.

(Polymerization of carbodiimide crosslinking agent)
A flask equipped with a stirrer, thermometer and reflux condenser was charged with 168 parts by mass of hexamethylene diisocyanate and 220 parts by mass of polyethylene glycol monomethyl ether (M400, average molecular weight 400), stirred at 120 ° C. for 1 hour, 26 parts by mass of 4′-dicyclohexylmethane diisocyanate and 3.8 parts by mass of 3-methyl-1-phenyl-2-phospholene-1-oxide (2% by mass based on the total isocyanate) as a carbodiimidization catalyst were added, and 185 under a nitrogen stream. Stir at 5 ° C. for a further 5 hours. An infrared spectrum of the reaction solution was measured, and it was confirmed that absorption at a wavelength of 2200 to 2300 cm ⁻¹ disappeared. It stood to cool to 60 degreeC, 567 mass parts of ion-exchange water was added, and carbodiimide water-soluble resin (V) with a solid content of 40 mass% was obtained.

(Epoxy-based crosslinking agent)
Denacol EX-521 (solid content concentration 100%) manufactured by Nagase ChemteX Corporation was used as the epoxy crosslinking agent (epoxy crosslinking agent (VI)).

(Melamine crosslinking agent)
As the melamine-based crosslinking agent, DIC's Becamine M-3 (solid content concentration 60%) was used (melamine-based crosslinking agent (VII)).

(Zirconia particles)
A 3 liter glass container was charged with 2283.6 g of pure water and 403.4 g of oxalic acid dihydrate and heated to 40 ° C. to prepare a 10.72 mass% oxalic acid aqueous solution. While stirring this aqueous solution, 495.8 g of zirconium oxycarbonate powder (ZrOCO ₃ , manufactured by AMR International Corp., containing 39.76% by mass in terms of ZrO ₂ ) was gradually added and mixed for 30 minutes. And heating at 90 ° C. for 30 minutes. Next, 1747.2 g of a 25.0 mass% tetramethylammonium hydroxide aqueous solution (manufactured by Tama Chemical Industry Co., Ltd.) was gradually added over 1 hour. At this point, the mixture was in the form of a slurry and contained 4.0% by mass in terms of ZrO ₂ . This slurry was transferred to a stainless steel autoclave container and hydrothermally treated at 145 ° C. for 5 hours. The product after the hydrothermal treatment was completely solated without any unpeptized material. The obtained sol contained 4.0% by mass as ZrO ₂ , pH 6.8, and the average particle size by dynamic light scattering method was 19 nm. Further, the transmittance measured by adjusting the sol to a ZrO ₂ concentration of 2.0% by mass with pure water was 88%. When the particles were observed with a transmission electron microscope, most of the aggregated particles of ZrO ₂ primary particles of around 7 nm were found. Using an ultrafiltration apparatus, 4000 g of zirconia sol having a ZrO ₂ concentration of 4.0% by mass obtained by performing the hydrothermal treatment was washed and concentrated while gradually adding pure water to obtain a ZrO ₂ concentration. As a result, 953 g of zirconia sol having a transmittance of 76% when 13.1% by mass, pH 4.9, and ZrO ₂ concentration of 13.1% by mass were obtained.

After adding 3.93 g of a 20 mass% citric acid aqueous solution and 11.0 g of a 25 mass% tetramethylammonium hydroxide aqueous solution to 300 g of a zirconia sol having a ZrO ₂ concentration of 13.1 mass% obtained by the above washing and concentration. Further, when concentration was performed with an ultrafiltration device, 129 g of high-concentration zirconia sol having a ZrO ₂ concentration of 30.5% by mass was obtained. The obtained high-concentration zirconia sol had a pH of 9.3 and an average particle diameter of 19 nm by a dynamic light scattering method. The zirconia sol had no precipitate and was stable for more than 1 month at 50 ° C.

(Titania particles)
12.09 kg of titanium tetrachloride aqueous solution containing 7.75% by mass of titanium tetrachloride (manufactured by Osaka Titanium Technologies Co., Ltd.) on a TiO ₂ basis and ammonia water containing 15% by mass of ammonia (manufactured by Ube Industries) ) 4.69 kg was mixed to prepare a white slurry having a pH of 9.5. Subsequently, this slurry was filtered and then washed with pure water to obtain 9.87 kg of a hydrous titanate cake having a solid content of 10% by mass. Next, 11.28 kg of hydrogen peroxide containing 35% by mass of hydrogen peroxide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 20.00 kg of pure water are added to the cake, and then at a temperature of 80 ° C. for 1 hour. The mixture was heated with stirring, and 57.52 kg of pure water was further added to obtain 98.67 kg of an aqueous solution of titanic acid peroxide containing 1% by mass of titanic acid peroxide on a TiO ₂ basis. This aqueous solution of titanic acid peroxide was transparent yellowish brown and had a pH of 8.5.

Next, 4.70 kg of cation exchange resin (manufactured by Mitsubishi Chemical Corporation) was mixed with 98.67 kg of the aqueous solution of titanic acid titanate, and potassium stannate (manufactured by Showa Kako Co., Ltd.) was converted into SnO _{2 in this.} 12.33 kg of an aqueous potassium stannate solution containing 1% by mass on a standard basis was gradually added with stirring. Next, after separating the cation exchange resin which took in potassium ion etc., it put into the autoclave (The pressure | voltage resistant glass industry Co., Ltd. product, 120L), and heated at the temperature of 165 degreeC for 18 hours.

Next, the obtained mixed aqueous solution was cooled to room temperature, and then concentrated with an ultrafiltration membrane device (ACV-3010, manufactured by Asahi Kasei Co., Ltd.). Hereinafter, 9.90 kg of an aqueous dispersion sol containing “P-1” was obtained. The solids contained in the sol thus obtained were measured by the above method. As a result, they were titanium-based fine particles (primary particles) having a rutile crystal structure and composed of a composite oxide containing titanium and tin. It was. Furthermore, when the content of the metal component contained in the titanium-based fine particles was measured, 87.2% by mass of TiO ₂ , 11.0% by mass of SnO ₂ , and K ₂ O based on the oxide conversion standard of each metal component. It was 1.8% by mass. The pH of the mixed aqueous solution was 10.0. Further, the water-dispersed sol containing the titanium-based fine particles is transparent milky white, the average particle size of the titanium-based fine particles contained in the water-dispersed sol is 35 nm, and coarse particles having a particle size of 100 nm or more. The distribution frequency was 0%. Furthermore, the refractive index of the obtained titanium-based fine particles could be regarded as 2.42.

(Zirconia / titania mixed particles)
The zirconia / titania mixed particles having a solid content concentration of 13% by mass were prepared by mixing the zirconia particles obtained above and titania particles at respective ratios.

(Formation of hard coat layer)
A coating liquid for forming a hard coat layer having the following composition was applied to the surface of the polyester film manufactured in the examples described later on the side opposite to the surface to be bonded to the polarizer, using a # 10 wire bar, and at 70 ° C. for 1 minute. Dry and remove the solvent. Next, the film coated with the hard coat layer was irradiated with 300 mJ / cm ² ultraviolet rays using a high-pressure mercury lamp to obtain a polarizer protective film having a hard coat layer with a thickness of 5 μm.
・ Coating liquid for hard coat layer formation
Methyl ethyl ketone 65.00% by mass
Dipentaerythritol hexaacrylate 27.20% by mass
(Shin-Nakamura Chemical A-DPH)
Polyethylene diacrylate 6.80% by mass
(Shin-Nakamura Chemical A-400)
Photopolymerization initiator 1.00% by mass
(Irgacure 184 manufactured by Ciba Specialty Chemicals)

Example 1
(Coating solution adjustment)
A coating solution having the following composition was prepared.
Water 34.94 parts by weight Isopropyl alcohol 30.00 parts by weight Particle A-1 7.24 parts by weight (Zirconia / titania mixed particles having an average particle diameter of 23 nm,
75% by mass of zirconia based on the total mass of zirconia / titania,
Solid content concentration 13% by mass)
Particle B-1 0.90 parts by mass (silica sol with an average particle diameter of 450 nm, solid content concentration 40% by mass)
Polyester aqueous dispersion (Iα) 17.92 parts by mass (solid content concentration 28.2% by mass)
Block isocyanate based crosslinking agent (III) 2.90 parts by mass (solid content concentration 75% by mass)
Surfactant 0.30 parts by mass (Fuso-based, solid content concentration 10% by mass)
High boiling point solvent 3.00 parts by weight Dispersing aid 0.26 parts by weight

(Manufacture of easily adhesive polyester film)
As the film raw material polymer, PET resin pellets having an intrinsic viscosity (solvent: phenol / tetrachloroethane = 60/40) of 0.62 dl / g and substantially free of particles are obtained at 135 ° C. under a reduced pressure of 133 Pa. Dry for hours. Thereafter, the sheet was supplied to an extruder, melted and extruded into a sheet at about 280 ° C., and rapidly cooled and solidified on a rotating cooling metal roll maintained at a surface temperature of 20 ° C. to obtain an unstretched PET sheet.

The unstretched PET sheet was heated to 100 ° C. with a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction with a roll group having a difference in peripheral speed to obtain a uniaxially stretched PET film.

Subsequently, after apply | coating the said coating liquid to the single side | surface of PET film by the roll coat method, it dried at 80 degreeC for 15 second. In addition, it adjusted so that the coating amount after drying after final extending | stretching might be 0.12 g / m < ² >. Subsequently, the film was stretched 4.0 times in the width direction at 150 ° C. with a tenter, and heated at 230 ° C. for 0.5 seconds with the length in the width direction fixed, and further at 230 ° C. for 10 seconds. % Relaxation treatment in the width direction was performed to obtain an easily adhesive polyester film having a thickness of 38 μm.

(Example 2)
Instead of the coating liquid particle A-1, an easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the ratio of the zirconia mass to the total mass of zirconia and titania was changed to the particle A-2 having a mass of 50 mass%. Got.

(Example 3)
Instead of the coating liquid particle A-1, an easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the ratio of the zirconia mass to the total mass of zirconia and titania was changed to the particle A-3 having a mass of 25 mass%. Got.

Example 4
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the coating solution having the following composition was prepared and used instead of the coating solution prepared and used in Example 1.
Water 37.23 parts by mass Isopropyl alcohol 30.00 parts by mass Particle A-1 3.79 parts by mass (Zirconia / titania mixed particles having an average particle diameter of 23 nm,
75% by mass of zirconia based on the total mass of zirconia / titania,
Solid content concentration 13% by mass)
Particle B-1 0.95 parts by mass (silica sol with an average particle diameter of 450 nm, solid content concentration 40% by mass)
Polyester aqueous dispersion (Iα) 18.77 parts by mass (solid content concentration 28.2% by mass)
Block isocyanate-based crosslinking agent (III) 3.03 parts by mass (solid content concentration 75% by mass)
Surfactant 0.30 parts by mass (Fuso-based, solid content concentration 10% by mass)
High boiling point solvent 3.00 parts by weight Dispersing aid 0.27 parts by weight

(Example 5)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the coating solution having the following composition was prepared and used instead of the coating solution prepared and used in Example 1.
Water 32.85 parts by weight Isopropyl alcohol 30.00 parts by weight Particle A-1 10.39 parts by weight (Zirconia / titania mixed particles having an average particle diameter of 23 nm,
75% by mass of zirconia based on the total mass of zirconia / titania,
Solid content concentration 13% by mass)
Particle B-1 0.87 parts by mass (silica sol with an average particle diameter of 450 nm, solid concentration 40% by mass)
Polyester aqueous dispersion (Iα) 17.15 parts by mass (solid content concentration 28.2% by mass)
Block isocyanate-based crosslinking agent (III) 2.80 parts by mass (solid content concentration 75% by mass)
Surfactant 0.30 parts by mass (Fuso-based, solid content concentration 10% by mass)
High boiling point solvent 3.00 parts by weight Dispersing aid 0.25 parts by weight

(Example 6)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the coating solution having the following composition was prepared and used instead of the coating solution prepared and used in Example 1.
Water 39.17 parts by weight Isopropyl alcohol 30.00 parts by weight Particle A-1 7.24 parts by weight (Zirconia / titania mixed particles having an average particle diameter of 23 nm,
75% by mass of zirconia based on the total mass of zirconia / titania,
Solid content concentration 13% by mass)
Particle B-1 0.90 parts by mass (silica sol with an average particle diameter of 450 nm, solid content concentration 40% by mass)
Polyurethane aqueous dispersion (II) 13.70 parts by mass (solid content concentration 37% by mass)
Block isocyanate based crosslinking agent (III) 2.90 parts by mass (solid content concentration 75% by mass)
Surfactant 0.30 parts by mass (Fuso-based, solid content concentration 10% by mass)
High boiling point solvent 3.00 parts by weight Dispersing aid 0.26 parts by weight

(Example 7)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the coating solution having the following composition was prepared and used instead of the coating solution prepared and used in Example 1.
Water 34.94 parts by weight Isopropyl alcohol 30.00 parts by weight Particle A-1 7.24 parts by weight (Zirconia / titania mixed particles having an average particle diameter of 23 nm,
75% by mass of zirconia based on the total mass of zirconia / titania,
Solid content concentration 13% by mass)
Particle B-1 0.90 parts by mass (silica sol with an average particle diameter of 450 nm, solid content concentration 40% by mass)
Polyester aqueous dispersion (Iα) 13.27 parts by mass (solid content concentration 28.2% by mass)
Polyurethane aqueous dispersion (II) 4.98 parts by mass (solid content concentration 37% by mass)
Block isocyanate based crosslinking agent (III) 2.90 parts by mass (solid content concentration 75% by mass)
Surfactant 0.30 parts by mass (Fuso-based, solid content concentration 10% by mass)
High boiling point solvent 3.00 parts by weight Dispersing aid 0.26 parts by weight

(Example 8)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the blocked isocyanate-based crosslinking agent (III) in the coating solution was changed to a water-soluble resin (IV) having an oxazoline group and the content was adjusted. It was.

Example 9
Block diisocyanate-based crosslinking agent (III) of coating solution is carbodiimide water-soluble resin (V)
The easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the content was adjusted.

(Example 10)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the blocked isocyanate-based crosslinking agent (III) in the coating solution was changed to the melamine-based crosslinking agent (VII) and the content thereof was adjusted.

(Example 11)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the blocked isocyanate crosslinking agent (III) in the coating solution was changed to the epoxy crosslinking agent (VI) and the content thereof was adjusted.

Example 12
An easily-adhesive polyester film was obtained in the same manner as in Example 1 except that the average particle diameter was changed to 40 nm particles A-4 instead of the coating solution particles A-1.

(Example 13)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the average particle diameter was changed to the particle A-5 having a thickness of 30 nm instead of the particle A-1 in the coating solution.

(Example 14)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the thickness of the coating layer was changed to 0.05 μm.

(Example 15)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the thickness of the coating layer was changed to 0.075 μm.

(Example 16)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the thickness of the coating layer was changed to 0.125 μm.

(Example 17)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the coating solution having the following composition was prepared and used instead of the coating solution prepared and used in Example 1.
Water 35.40 parts by mass Isopropyl alcohol 30.00 parts by mass Particle A-1 7.26 parts by mass (Zirconia / titania mixed particles having an average particle diameter of 23 nm,
75% by mass of zirconia based on the total mass of zirconia / titania,
Solid content concentration 13% by mass)
Particle B-1 0.36 parts by mass (silica sol having an average particle diameter of 450 nm, solid content concentration of 40% by mass)
Polyester aqueous dispersion (Iα) 17.98 parts by mass (solid content concentration 28.2% by mass)
Block isocyanate based crosslinking agent (III) 2.90 parts by mass (solid content concentration 75% by mass)
Surfactant 0.30 parts by mass (Fuso-based, solid content concentration 10% by mass)
High boiling point solvent 3.00 parts by weight Dispersing aid 0.26 parts by weight

(Example 18)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the coating solution having the following composition was prepared and used instead of the coating solution prepared and used in Example 1.
Water 34.48 parts by weight Isopropyl alcohol 30.00 parts by mass Particle A-1 7.22 parts by mass (Zirconia / titania mixed particles having an average particle diameter of 23 nm,
75% by mass of zirconia based on the total mass of zirconia / titania,
Solid content concentration 13% by mass)
Particle B-1 1.44 parts by mass (silica sol with an average particle diameter of 450 nm, solid concentration 40% by mass)
Polyester aqueous dispersion (Iα) 17.88 parts by mass (solid content concentration 28.2% by mass)
Block isocyanate based crosslinking agent (III) 2.90 parts by mass (solid content concentration 75% by mass)
Surfactant 0.30 parts by mass (Fuso-based, solid content concentration 10% by mass)
High boiling point solvent 3.00 parts by weight Dispersing aid 0.26 parts by weight

(Comparative Example 1)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the coating liquid particles A-1 were replaced with non-mixed zirconia single particles A-6 containing no titania.

(Comparative Example 2)
The same procedure as in Example 1 was conducted, except that the coating liquid particle A-1 was replaced with non-mixed titania-based single particle A-7 containing no zirconia and the mass% was adjusted in consideration of the solid content concentration. An easily adhesive polyester film was obtained.

(Comparative Example 3)
An easy-adhesive polyester film was obtained in the same manner as in Example 1 except that the coating solution having the following composition was prepared and used instead of the coating solution prepared and used in Example 1.
Water 35.71 parts by mass Isopropyl alcohol 30.00 parts by mass Particle A-1 7.27 parts by mass (Zirconia / titania mixed particles having an average particle diameter of 23 nm,
75% by mass of zirconia based on the total mass of zirconia / titania,
Solid content concentration 13% by mass)
Polyester aqueous dispersion (Iα) 28.58 parts by mass (solid content concentration 28.2% by mass)
Block isocyanate-based crosslinking agent (III) 1.38 parts by mass (solid content concentration 75% by mass)
Surfactant 0.30 parts by mass (Fuso-based, solid content concentration 10% by mass)
High boiling point solvent 3.00 parts by weight Dispersing aid 0.26 parts by weight

The easy-adhesive polyester film obtained in each example has good scratch resistance, moderate static friction coefficient and dynamic friction coefficient, and is satisfactory in each evaluation item of transparency, adhesion, moist heat resistance, and low interference. A good result was obtained. On the other hand, the easily adhesive polyester film obtained in Comparative Example 1 was not satisfactory in heat and moisture resistance because the particles A in the coating layer did not contain zirconia. Moreover, since the easily adhesive polyester film obtained by Comparative Example 2 did not contain titania in the particles A in the coating layer, it was not satisfactory in scratch resistance. And since the easily adhesive polyester film obtained by the comparative example 3 does not contain the lubricant particles B in the coating layer, the coefficient of friction was large.

(Example 19)
On the coating layer of the easy-adhesive polyester film obtained in Example 1, a coating solution for forming an antiglare layer having the following composition was applied using a # 5 wire bar and dried at 70 ° C. for 1 minute to remove the solvent. did. Next, the film coated with the antiglare layer was irradiated with 300 mJ / cm ² of ultraviolet light using a high-pressure mercury lamp to obtain a laminated polyester film having an antiglare layer having a thickness of 5 μm. A preferred laminated polyester film having an antiglare property was obtained.
・ Coating solution for antiglare layer formation
34 parts by mass of toluene
50 parts by mass of pentaerythritol triacrylate
Silica (average particle size 1 μm) 12 parts by mass
Silicone (leveling agent) 1 part by mass
1 part by weight of photopolymerization initiator
(Irgacure 184 manufactured by Ciba Specialty Chemicals)

(Example 20)
On the coating layer of the easily adhesive polyester film obtained in Example 1, a medium refractive index layer-forming coating solution having the following composition was coated using a bar coater, dried at 70 ° C. for 1 minute, and then using a high-pressure mercury lamp. Irradiation with ultraviolet rays of 400 mJ / cm ² yielded a medium refractive index layer having a dry film thickness of 5 μm. Next, on the formed medium refractive index layer, using a bar coater, a coating solution for forming a high refractive index layer having the following composition is formed by the same method as that for the medium refractive index layer. A coating solution for forming a low refractive index layer was formed by the same method as that for the middle refractive index layer to obtain a laminated polyester film on which an antireflection layer was laminated. A preferred laminated polyester film having antireflection properties was obtained.

・ Medium refractive index layer coating solution (refractive index 1.52)
70 parts by mass of dipentaerythritol hexaacrylate
1,6-bis (3-acryloyloxy-2-hydroxypropyloxy) hexane
30 parts by mass
4 parts by mass of photopolymerization initiator
(Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.)
100 parts by mass of isopropanol
・ High refractive index layer coating solution (refractive index 1.64)
ITO fine particles (average particle size 0.07 μm) 85 parts by mass
Tetramethylol methane triacrylate 15 parts by mass
Photopolymerization initiator (KAYACURE BMS, Nippon Kayaku) 5 parts by mass
900 parts by weight of butyl alcohol
・ Low refractive index layer coating solution (refractive index 1.42)
1,10-Diacryloyloxy-2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluorodecane 70 parts by mass
Dipentaerythritol hexaacrylate 10 parts by mass
Silica gel fine particles (XBA-ST, manufactured by Nissan Chemical Co., Ltd.) 60 parts by mass
Photopolymerization initiator (KAYACURE BMS, Nippon Kayaku) 5 parts by mass

Claims

A polyester film having a coating layer on at least one side, wherein the coating layer contains zirconia / titania mixed particles A, lubricant particles B, and a binder resin, and is based on the total mass of zirconia and titania in the zirconia / titania mixed particles A. An easily adhesive polyester film having a zirconia content of 10 to 90% by mass and an average particle diameter of the lubricant particles B of 200 nm or more.
2. The easily adhesive polyester film according to claim 1, wherein the average particle diameter of the zirconia / titania mixed particles A is 5 to 200 nm.
The easily adhesive polyester film according to claim 1 or 2, wherein the content of the lubricant particles B with respect to the solid content of the coating layer is 0.1 to 20% by mass.
The easily adhesive polyester film according to any one of claims 1 to 3, wherein the content of the zirconia / titania mixed particles A with respect to the solid content of the coating layer is 2 to 50 mass%.
5. The coating layer of the easy-adhesive polyester film according to claim 1, wherein the hard coat layer, the antiglare layer, the antiglare antireflection layer, the antireflection layer, and the low reflection layer are selected. A laminated polyester film having one or more functional layers.